[Federal Register Volume 68, Number 1 (Thursday, January 2, 2003)]
[Rules and Regulations]
[Pages 18-23]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-32684]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-CE-54-AD; Amendment 39-12991; AD 2002-26-05]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. Models AT-502, AT-
502A, AT-502B, and AT-503A Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This amendment supersedes Airworthiness Directive (AD) 2002-
11-03, which applies to certain Air Tractor, Inc. (Air Tractor) Models 
AT-502, AT-502A, AT-502B, and AT-503A airplanes. AD 2002-11-03 lowered 
the safe life for the wing lower spar cap and further reduced the safe 
life for airplanes that incorporate or have incorporated Marburger 
Enterprises, Inc. winglets. AD 2002-11-03 also currently requires you 
to eddy-current inspect the wing lower spar cap immediately prior to 
the replacement/modification to detect and correct any crack in a 
bolthole before it extends to the modified center section of the wing 
and report the results of this inspection to the Federal Aviation 
Administration (FAA). Field inspections on the affected airplanes have 
revealed wings with cracks below the currently established safe life. 
This AD would further reduce the safe life of the Models AT502, AT-
502B, and AT-503A airplanes and would add airplanes recently 
manufactured to the Applicability of the AD. The actions specified by 
this AD are intended to prevent fatigue cracks from occurring in the 
wing lower spar cap before the established safe life is reached. 
Fatigue cracks in the wing lower spar cap, if not detected and 
corrected, could result in the wing separating from the airplane during 
flight.

DATES: This AD becomes effective on January 15, 2003.
    The Director of the Federal Register previously approved the 
incorporation by reference of certain publications listed in the 
regulation as of June 8, 2001 (66 FR 27014, May 16, 2001).
    The FAA must receive any comments on this rule on or before 
February 14, 2003.

ADDRESSES: Submit comments to FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2002-CE-54-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106. You may view any 
comments at this location between 8 a.m. and 4 p.m., Monday through 
Friday, except Federal holidays. You may also send comments 
electronically to the following address: [email protected]. 
Comments sent electronically must contain ``Docket No. 2002-CE-54-AD'' 
in the subject line. If you send comments electronically as attached 
electronic files, the files must be formatted in Microsoft Word 97 for 
Windows or ASCII text.
    You may get the service information referenced in this AD from Air 
Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374; or Marburger 
Enterprises, Inc., 1227 Hillcourt, Williston, North Dakota 58801; 
telephone: (800) 893-1420 or (701) 774-0230; facsimile: (701) 572-2602. 
You may view this information at FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2002-CE-54-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the 
Federal Register, 800 North Capitol Street, NW, suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Direct all questions to:

--For the airplanes that do not incorporate and never have incorporated 
Marburger Enterprises, Inc. winglets: Rob Romero, Aerospace Engineer, 
FAA, Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, 
Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: 
(817) 222-5960; and
--For airplanes that incorporate or have incorporated Marburger 
Enterprises, Inc. winglets: John Cecil, Aerospace Engineer, Los Angeles 
Aircraft Certification Office, FAA, 3960 Paramount Boulevard, Lakewood, 
California 90712; telephone: (562) 627-5228; facsimile: (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Discussion

    Has FAA taken any action to this point? On December 17, 2001, FAA 
issued a proposal to amend part 39 of the Federal Aviation Regulations 
(14 CFR part 39) to include an AD that would apply to certain Air 
Tractor, Inc. (Air Tractor) AT-400, AT-500, and AT-800 series 
airplanes. This proposal was published in the Federal Register as a 
notice of proposed rulemaking (NPRM) on December 27, 2001 (66 FR 
66823). The NPRM proposed to supersede AD 2001-10-04 R1 with a new AD 
that would retain the safe life for the wing lower spar cap and require 
you to eddy-current inspect the wing lower spar cap immediately prior 
to the replacement/modification to detect and correct any crack in a 
bolthole before it extends to the modified center section of the wing. 
The NPRM also proposed to further reduce the safe life for those AT-400 
and AT-500 series airplanes that incorporate or have incorporated 
Marburger Enterprises, Inc. winglets.
    After issuing that NPRM, we received reports of several cracks 
originating in the outboard \3/8\-inch hole of the main spar lower cap 
on Air Tractor Models AT--502, AT-502A, and AT-502B airplanes at hours 
time-in-service (TIS) lower than the established safe life. This caused 
us to issue AD 2002-11-03, Amendment 39-12764 (67 FR 38371, June 4, 
2002). AD 2002-11-03 lowers the safe life for the wing lower spar cap 
established in AD 2001-10-04 R1 on Air Tractor Models AT-502, AT-502A, 
AT-502B, and AT-503A airplanes and further reduces the safe life for 
airplanes that incorporate or have incorporated Marburger Enterprises, 
Inc. winglets.
    We issued a separate AD for the Air Tractor AT-400 and AT-800 
series airplanes.
    What has happened since AD 2002-11-03 to initiate This action? 
Field inspections have revealed wings with cracks below the currently 
established safe life on Air Tractor Models AT 502, AT-502B, and AT-
503A airplanes.

    In addition, the Applicability of AD 2002-11-03 only covered serial 
number airplanes of the Models AT-502A and AT-502B that were already 
manufactured. The Applicability did not account for airplanes 
manufactured after the issuance of the AD.

The FAA's Determination and an Explanation of the Provisions of This AD

    What has FAA decided? The FAA has reviewed all available 
information and determined that:

--The unsafe condition referenced in this document exists or could 
develop on other Air Tractor Models AT-502, AT-502A, AT-502B, and AT-
503A airplanes of the same type design;
--The safe life on the Models AT-502, AT-502B, and AT-503A airplanes 
should be further reduced;
--The serial number range of the Models AT-502A and AT-502B airplanes 
should be expanded to

[[Page 19]]

include future manufactured airplanes; and
--Final rule; request for comments (immediately adopted rule) AD action 
should be taken to address this condition.

    What does this AD require? This AD will supersede AD 2002-11-03 and 
will:

--Maintain the requirements of a lowered safe life, inspection, 
replacement/modification, and reporting the results to FAA;
--Further lower the safe life for the wing lower spar cap established 
in AD 2002-11-03 for the Models AT-502, AT-502B, and AT-503A airplanes; 
and
--Expand the applicability of the Models AT-502A and AT-502B airplanes 
to account for future manufactured airplanes.

    You must accomplish these actions in accordance with Snow 
Engineering Service Letter 197 or 205, both Revised 
March 26, 2001, as applicable.
    In preparation of this rule, we contacted type clubs and aircraft 
operators to obtain technical information and information on 
operational and economic impacts. We did not receive any information 
through these contacts. If received, we would have included, in the 
rulemaking docket, a discussion of any information that may have 
influenced this action.
    Will I have the opportunity to comment prior to the issuance of the 
rule? Because the unsafe condition described in this document could 
result in the wing separating from the airplane during flight, we find 
that notice and opportunity for public prior comment are impracticable. 
Therefore, good cause exists for making this amendment effective in 
less than 30 days.

Comments Invited

    How do I comment on this AD? Although this action is in the form of 
a final rule and was not preceded by notice and opportunity for public 
comment, FAA invites your comments on the rule. You may submit whatever 
written data, views, or arguments you choose. You need to include the 
rule's docket number and submit your comments to the address specified 
under the caption ADDRESSES. We will consider all comments received on 
or before the closing date specified above. We may amend this rule in 
light of comments received. Factual information that supports your 
ideas and suggestions is extremely helpful in evaluating the 
effectiveness of the AD action and determining whether we need to take 
additional rulemaking action.
    Are there any specific portions of the AD I should pay attention 
to? We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. You may view all comments we receive 
before and after the closing date of the rule in the Rules Docket. We 
will file a report in the Rules Docket that summarizes each FAA contact 
with the public that concerns the substantive parts of this AD.
    How can I be sure FAA receives my comment? If you want us to 
acknowledge the receipt of your comments, you must include a self-
addressed, stamped postcard. On the postcard, write ``Comments to 
Docket No. 2002-CE-54-AD.'' We will date stamp and mail the postcard 
back to you.

Regulatory Impact

    Does this AD impact various entities? These regulations will not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government. 
Therefore, FAA has determined that this final rule does not have 
federalism implications under Executive Order 13132.
    Does this AD involve a significant rule or regulatory action? We 
have determined that this regulation is an emergency regulation that 
must be issued immediately to correct an unsafe condition in aircraft, 
and is not a significant regulatory action under Executive Order 12866. 
It has been determined further that this action involves an emergency 
regulation under DOT Regulatory Policies and Procedures (44 FR 11034, 
February 26, 1979). If it is determined that this emergency regulation 
otherwise would be significant under DOT Regulatory Policies and 
Procedures, a final regulatory evaluation will be prepared and placed 
in the Rules Docket (otherwise, an evaluation is not required). A copy 
of it, if filed, may be obtained from the Rules Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

    2. FAA amends Sec.  39.13 by removing Airworthiness Directive (AD) 
2002-11-03, Amendment 39-12764 (67 FR 38371, June 4, 2002), and by 
adding a new AD to read as follows:

2002-26-05 Air Tractor, Inc.: Amendment 39-12991; Docket No. 2002-
CE-54-AD. Supersedes AD 2002-11-03, Amendment 39-12764.

    (a) What airplanes are affected by this AD? This AD applies to 
certain Models AT-502, AT-502A, AT-502B, and AT-503A airplanes. Use 
paragraph (a)(1) of this AD for airplanes that do not incorporate 
and never have incorporated winglets. Use paragraph (a)(3) of this 
AD for certain AT-500 series airplanes that incorporate or have 
incorporated Marburger Enterprises, Inc. winglets.
    (1) The following presents airplanes (certificated in any 
category) that are affected by this AD, along with the new safe life 
(presented in hours time-in-service (TIS)) of the wing lower spar 
cap for all affected airplane models and serial numbers:

----------------------------------------------------------------------------------------------------------------
                 Model                                 Serial Nos.                           Safe life
----------------------------------------------------------------------------------------------------------------
AT-502................................  0003 through 0236.......................  1,650 hours TIS
AT-502A...............................  All serial numbers beginning with 0158..  1,650 hours TIS
AT-502B...............................  All serial numbers beginning with 0187..  1,650 hours TIS
AT-503A...............................  All serial numbers beginning with 0067..  1,650 hours TIS
----------------------------------------------------------------------------------------------------------------

    (2) If piston powered aircraft have been converted to turbine 
power, you must use the limits for the corresponding serial number 
turbine-powered aircraft.

[[Page 20]]

    (3) The following presents airplanes (certificated in any 
category) that could incorporate or could have incorporated 
Marburger Enterprises, Inc. winglets. These winglets are installed 
in accordance with Supplemental Type Certificate (STC) SA00490LA. 
Use the winglet usage factor in the table below, the safe life 
specified in paragraph (a)(1) of this AD, and the instructions 
included in the Appendix to this AD to determine the new safe life 
of these airplanes:

------------------------------------------------------------------------
                                                                Winglet
            Model                        Serial Nos.             usage
                                                                 factor
------------------------------------------------------------------------
AT-502.......................  0003 through 0236.............        1.6
AT-502A......................  0158 through 0238.............        1.6
AT-502A......................  All serial numbers beginning          1.2
                                with 0239.
AT-502B......................  All serial numbers beginning          1.2
                                with 0187.
------------------------------------------------------------------------

    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the airplanes identified in paragraph (a) of this AD must 
comply with this AD.
    (c) What problem does this AD address? The actions specified by 
this AD are intended to prevent fatigue cracks from occurring in the 
wing lower spar cap before the established safe life is reached. 
Fatigue cracks in the wing lower spar cap, if not detected and 
corrected, could result in the wing separating from the airplane 
during flight.
    (d) What must I do to address this problem? To address this 
problem, you must accomplish the following actions:

------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Modify the applicable     Accomplish the        The owner/operator
 aircraft records (logbook)    logbook entry         holding at least a
 as follows to show the        within the next 10    private pilot
 reduced safe life for the     hours TIS after       certificate as
 wing lower spar cap (use      January 15, 2003      authorized by
 the information from          (the effective date   section 43.7 of the
 paragraphs (a)(1) and         of this AD).          Federal Aviation
 (a)(3) of this AD and the                           Regulations (14 CFR
 Appendix to this AD, as                             43.7) may modify
 applicable):.                                       the aircraft
(i) Incorporate the                                  records as
 following into the Aircraft                         specified in
 Logbook ``In accordance                             paragraphs
 with AD 2002-26-05, the                             (d)(1)(i) and
 wing lower spar cap is life                         (d)(1)(ii) of this
 limited to --.'' Insert the                         AD. Make an entry
 applicable safe life number                         into the aircraft
 from the applicable tables                          records showing
 in paragraphs (a)(1) and                            compliance with
 (a)(3) of this AD and the                           this portion of the
 Appendix to this AD..                               AD in accordance
(ii) If, as of the time of                           with section 43.9
 the logbook entry                                   of the Federal
 requirement of paragraph                            Aviation
 (d)(1)(i) of this AD, your                          Regulations (14 CFR
 airplane is over or within                          43.9). Accomplish
 50 hours of the safe life,                          the actual
 an additional 50 hours TIS                          replacement/
 is allowed to accomplish                            modification in
 the replacement/                                    accordance with
 modification..                                      Snow Engineering
                                                     Service Letter
                                                     197 or
                                                     205, both
                                                     Revised March 26,
                                                     2001, as
                                                     applicable. The
                                                     owner/operator may
                                                     not accomplish the
                                                     replacement/
                                                     modification,
                                                     unless he/she holds
                                                     the proper mechanic
                                                     authorization.
(2) You may eddy-current      Inspect prior to      In accordance with
 inspect the wing lower spar   further flight        the procedures in
 cap instead of                after ordering the    Snow Engineering
 accomplishing the             parts and             Service Letter
 replacement/modification      scheduling a          197 or
 provided you have ordered     replacement/          205, both
 parts from the factory and    modification date,    Revised March 26,
 scheduled a replacement/      and inspect           2001, as
 modification date when it     thereafter at         applicable.
 is time to replace the wing   intervals not to
 lower spar cap (as required   exceed 400 hours
 when you reach the            TIS until one of
 established safe life).       the criteria in
 These inspections are         paragraphs
 allowed until one of the      (d)(2)(i) and
 following occurs, at which    (d)(2)(ii) of this
 time the replacement/         AD is met.
 modification must be
 accomplished:.
(i) Crack(s) is/are found;
 or.
(ii) Not more than three
 inspections or 1,200 hours
 TIS go by: the first
 inspection would have to be
 accomplished upon
 accumulating the safe life;
 the second inspection would
 have to be accomplished
 within 400 hours TIS after
 accumulating the safe life;
 the third inspection would
 have to be accomplished 400
 hours TIS after the second
 inspection; and the
 replacement/modification
 would have to be
 accomplished within 400
 hours TIS after the third
 inspection (maximum elapsed
 time would be 1,200 hours
 TIS)..

[[Page 21]]

 
(3) Eddy-current inspect the  Immediately prior to  In accordance with
 wing lower spar cap in        the replacement/      the procedures in
 order to detect any crack     modification          Snow Engineering
 before it extends to the      required when you     Service Letter
 modified center section of    reach the new safe    197 or
 the wing and repair any       life. For airplanes   205, both
 crack or replace the wing     that had this         Revised March 26,
 section. The inspection       replacement/          2001, as
 must be accomplished by one   modification          applicable.
 of the following:.            accomplished in
(i) A Level 2 or Level 3       accordance with
 inspector that is certified   either AD 2001-10-
 for eddy-current inspection   04 or AD 2001-10-04
 using the guidelines          R1, accomplish this
 established by the American   inspection and any
 Society for Nondestructive    necessary
 Testing or MIL-STD-410; or.   corrective action
(ii) A person authorized to    within the next 400
 perform AD work who has       hours TIS after
 completed and passed the      June 14, 2002 (the
 Air Tractor, Inc. training    effective date of
 course on Eddy Current        AD 2002-11-03),
 Inspection on wing lower      unless already
 spar caps..                   accomplished (have
                               the mechanic who
                               accomplished the
                               work mark the
                               logbooks
                               accordingly).
(4) Report to FAA the         Within 10 days after  Submit the form
 results of each inspection    the inspection        (Figure 1 of this
 required by paragraph         required in           AD) to FAA, Fort
 (d)(3) of this AD. The        paragraph (d)(3) of   Worth Airplane
 Office of Management and      this AD or within     Certification
 Budget (OMB) approved the     10 days after June    Office, 2601
 information collection        14, 2002 (the         Meacham Boulevard,
 requirements contained in     effective date of     Fort Worth, Texas
 this regulation under the     AD 2002-11-03),       76193-0150;
 provisions of the Paperwork   whichever occurs      telephone: (817)
 Reduction Act of 1980 (44     later.                222-5102;
 U.S.C. 3501 et seq.) and                            facsimile: (817)
 assigned OMB Control Number                         222-5960.
 2120-0056.
------------------------------------------------------------------------


    Note 1: Upon completion of the replacement/modification required 
by this AD, the safe life of the new/modified wing spar is limited 
to the applicable hours listed in paragraph (a)(1) of this AD. This 
new life limit starts at the time of the replacement/modification.


                     AD 2002-26-05 Inspection Report
------------------------------------------------------------------------
 
------------------------------------------------------------------------
1. Inspection Performed By:                 2. Phone:
3. Aircraft Model                           4. Aircraft Serial Number:
-------------------------------------------
5. Engine Model Number:                     6. Aircraft Total TIS:
-------------------------------------------
7. Wing Total TIS:                          8. Lower Spar Cap TIS:
-------------------------------------------
9. Has the lower spar cap been inspected    9a. If yes,
 before? (Eddy-current, Dye penetrant,      Date: --------------------
 magnetic particle, ultrasound)             Inspection Method: ----------
 [ballot]Yes [ballot]No                      ----------
                                            Lower Spar Cap TIS:
                                             --------------------
                                            Cracks found? [ballot]
                                             [ballot]No
-------------------------------------------
10. Has there been any major repair or      10a. If yes, specify
 alteration performed to the spar cap?       (Description and TIS)
 [ballot]Yes [ballot]No
-------------------------------------------
11. Date of AD inspection: ----------------------------------------------
 --------------
------------------------------------------------------------------------
12. Inspection Results:                     12a.
Note: Indicate even if no cracks are         [ballot]Left Hand
 found.                                      [ballot]Right Hand
-------------------------------------------
12b.                                        12c. Does drilling hole to
 Crack Length: ----------------------------  next larger size remove all
 --                                          traces of the crack(s)?
                                             [ballot]Yes [ballot]No
-------------------------------------------
12d. Corrective Action Taken:
 
 
------------------------------------------------------------------------
                 Figure 1 of paragraph (d)(4) of this AD

    (e) Can I comply with this AD in any other way?
    (1)You may use an alternative method of compliance or adjust the 
compliance time if:
    (i) Your alternative method of compliance provides an equivalent 
level of safety; and
    (ii) The Manager, Fort Worth or Los Angeles Airplane 
Certification Office (ACO), as applicable, approves your 
alternative. Submit your request through an FAA Principal 
Maintenance Inspector. The inspector may add comments before sending 
it to the Manager, Fort Worth or Los Angeles ACO.
    (2) Alternative methods of compliance approved for AD 2001-10-04 
and/or AD 2000-14-51 are not considered approved for this AD.
    (3) Alternative methods of compliance approved for AD 2001-10-04 
R1 or AD 2002-11-03 are considered approved for this AD.

    Note 2: This AD applies to each airplane identified in 
paragraphs (a)(1) and (a)(3) of this AD, regardless of whether it 
has been modified, altered, or repaired in the area subject to the 
requirements of this AD. For

[[Page 22]]

airplanes that have been modified, altered, or repaired so that the 
performance of the requirements of this AD is affected, the owner/
operator must request approval for an alternative method of 
compliance in accordance with paragraph (e) of this AD. The request 
should include an assessment of the effect of the modification, 
alteration, or repair on the unsafe condition addressed by this AD; 
and, if you have not eliminated the unsafe condition, specific 
actions you propose to address it.

    (f) Who can I contact with questions about this AD? For more 
information about the subject matter specified in this AD, contact:
    (i) For the airplanes that do not incorporate and never have 
incorporated Marburger Enterprises, Inc. winglets: Rob Romero, 
Aerospace Engineer, FAA, Fort Worth Airplane Certification Office, 
2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: 
(817) 222-5102; facsimile: (817) 222-5960; and
    (ii) For the airplanes that incorporate or have incorporated 
winglets: John Cecil, Aerospace Engineer, Los Angeles Aircraft 
Certification Office, FAA, 3960 Paramount Boulevard, Lakewood, 
California 90712; telephone: (562) 627-5228; facsimile: (562) 627-
5210.
    (g) What if I need to fly the airplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
Sec. Sec.  21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate your airplane to a location where 
you can accomplish the requirements of this AD provided that the 
following is adhered to:
    (1) Only operate in day visual flight rules (VFR) only.
    (2) Ensure that the hopper is empty.
    (3) Limit airspeed to 135 miles per hour (mph) indicated 
airspeed (IAS).
    (4) Avoid any unnecessary g-forces.
    (5) Avoid areas of turbulence.
    (6) Plan the flight to follow the most direct route.
    (h) Are any service bulletins incorporated into this AD by 
reference? Replacement and inspection actions required by this AD 
must be done in accordance with Snow Engineering Service Letter 
197 or 205, both Revised March 26, 2001, as 
applicable. The Director of the Federal Register previously approved 
this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 
51, as of June 8, 2001 (66 FR 27014, May 16, 2001). You can get 
copies from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 
76374; or Marburger Enterprises, Inc., 1227 Hillcourt, Williston, 
North Dakota 58801. You may view copies at FAA, Central Region, 
Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, 
Missouri, or at the Office of the Federal Register, 800 North 
Capitol Street, NW, suite 700, Washington, DC.
    (i) When does this amendment become effective? This amendment 
becomes effective on January 15, 2003.

Appendix to AD 2002-26-05

    The following provides procedures for determining the safe life 
for Models AT-502, AT-502A, and AT-502B airplanes that incorporate 
or have incorporated Marburger Enterprises, Inc. winglets. These 
winglets are installed in accordance with Supplemental Type 
Certificate (STC) SA00490LA.

What If I Removed the Marburger Winglets Prior to Further Flight 
After the Effective Date of This AD or Prior to the Effective Date 
of This AD?

    1. Review your airplane's logbook to determine your airplane's 
time-in-service (TIS) with winglets installed per Marburger 
Enterprises STC SA00490LA. This includes all time spent with the 
winglets currently installed and any previous installations where 
the winglet was installed and later removed.

    Example:  A review of your airplane's logbook shows that you 
have accumulated 350 hours TIS since incorporating the Marburger 
STC. Further review of the airplane's logbook shows that a previous 
owner had installed the STC and later removed the winglets after 
accumulating 150 hours TIS. Therefore, your airplane's TIS with the 
winglets installed is 500 hours.

    If you determine that the winglet STC has never been 
incorporated on your airplane, then your safe life is presented in 
paragraph (a)(1) of this AD. Any future winglet installation will be 
subject to a reduced safe life per these instructions.
    2. Determine your airplane's unmodified safe life from paragraph 
(a)(1) of this AD.

    Example:  Your airplane is a Model AT-502B, serial number 0292. 
From paragraph (a)(1) of this AD, the safe life of your airplane is 
1,650 hours TIS.
    All examples from hereon will be based on the Model AT-502B, 
serial number 0292 airplane.

    3. Determine the winglet usage factor from paragraph (a)(3) of 
this AD.

    Example:  Again, your airplane is a Model AT-502B, serial number 
0292. From paragraph (a)(3) of this AD, your winglet usage factor is 
1.2.

    4. Adjust the winglet TIS to account for the winglet usage 
factor. Multiply the winglet TIS (result of Step 1 above) by the 
winglet usage factor (result of Step 3 above).
    Example: Winglet TIS is 500 hours X a winglet usage factor of 
1.2. The adjusted winglet TIS is 600 hours.

    5. Calculate the winglet usage penalty. Subtract the winglet TIS 
(result of Step 1 above) from the adjusted winglet TIS (result of 
Step 4 above).

    Example: 
Adjusted winglet TIS--the winglet TIS = winglet usage penalty.
(600 hours) -- (500 hours TIS) =(100 hours TIS).

    6. Adjust the safe life of your airplane to account for winglet 
usage. Subtract the winglet usage penalty (result of Step 5 above) 
result from the unmodified safe life from paragraph (a)(1) of this 
AD (result of Step 2 above).

    Example: 
Unmodified safe life--winglet usage penalty = adjusted safe life.
(1,650 hours TIS)--(100 hours TIS) = (1,550 hours TIS).
    7. If you remove the winglets from your airplane prior to 
further flight or no longer have the winglets installed on your 
airplane, the safe life of your airplane is the adjusted safe life 
(result of Step 6 above). Enter this number in paragraph (d)(1)(i) 
of this AD and the airplane logbook.

What If I have the Marburger Winglet Installed as of the Effective 
Date of This AD and Plan To Operate My Airplane Without Removing 
the Winglet?

    1. Review your airplane's logbook to determine your airplane's 
TIS without the winglets installed.

    Example: 
    A review of your airplane's logbook shows that you have 
accumulated 1,500 hours TIS, including 500 hours with the Marburger 
winglets installed. Therefore, your airplane's TIS without the 
winglets installed is 1,000 hours.

    2. Determine your airplane's unmodified safe life from paragraph 
(a)(1) of this AD.

    Example: Your airplane is a Model AT-502B, serial number 0292. 
From paragraph (a)(1) of this AD, the safe life of your airplane is 
1,650 hours TIS.
    All examples from hereon will be based on the Model AT-502B, 
serial number 0292 airplane.

    3. Determine the winglet usage factor from paragraph (a)(3) of 
this AD.

    Example: Again, your airplane is a Model AT-502B, serial number 
0292. From paragraph (a)(3) of this AD, your winglet usage factor is 
1.2.

    4. Determine the potential winglet TIS. Subtract the TIS without 
the winglets installed (result of Step 1 above) from the unmodified 
safe life (result of Step 2 above).

    Example: 
Unmodified safe life--TIS without winglets = Potential winglet TIS.
(1,650 hours TIS) `` (1,000 hours TIS) = (650 hours TIS).

    5. Adjust the potential winglet TIS to account for the winglet 
usage factor. Divide the potential winglet TIS (result of Step 4 
above) by the winglet usage factor (result of Step 3 above).


    Example: 
Potential winglet TIS divided by usage factor = Adjusted potential 
winglet TIS.
(650 hours TIS) / (1.2) = (542 hours TIS).
    6. Calculate the winglet usage penalty. Subtract the adjusted 
potential winglet TIS (result of Step 5 above) from the potential 
winglet TIS (result of Step 4 above).


    Example: 
Potential winglet TIS--Adjusted potential winglet TIS = Winglet 
usage penalty.
(650 hours TIS) -- (542 hours TIS) = (108 hours TIS).

    7. Adjust the safe life of your airplane to account for the 
winglet installation. Subtract the winglet usage penalty (result of 
Step 6 above) from the unmodified safe life from paragraph (a)(1) of 
this AD (result of Step 2 above).


    Example: 
Unmodified safe life--Winglet usage penalty = Adjusted safe life.

[[Page 23]]

(1,650 hours TIS)--(108 hours TIS) = (1,542 hours TIS).

    8. Enter the adjusted safe life (result of Step 7 above) in 
paragraph (d)(1)(i) of this AD and the airplane logbook.

What If I Install or Remove the Marburger Winglet From My Airplane 
in the Future?

    If, at anytime in the future, you install or remove the 
Marburger winglet STC from your airplane, you must repeat the 
procedures in this Appendix to determine the airplane's safe life.

    Issued in Kansas City, Missouri, on December 20, 2002.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-32684 Filed 12-31-02; 8:45 am]
BILLING CODE 4910-13-U